The Myth of the Irrational Mother

By Will Wilkinson

Everett Collection

While I marvel at my friend Bryan Caplan’s tenacity in making the case that parents should have more kids, I continue to find his line of argument simply bewildering.

According to Mr. Caplan, twins studies show that “the effect of parenting on adult outcomes ranges from small to zero” for children raised in “vaguely normal First World families,” and this implies that parents are “overcharging” themselves emotionally for each child, leading many of us to “buy” too few kids. “When you learn that something you want is cheaper than you thought,” Mr. Caplan maintains, “both common sense and basic economics tell you to buy more.”

Let’s start with the last claim first. Suppose I’ve got my eye on a certain hi-definition television set. I think it costs $1,000, which is exactly what I’ve got to spend. Then I discover it’s on sale for $900. Should I buy two? Three? Should I take the hundred bucks I saved and put it toward more TVs? I suspect Mr. Caplan’s “just relax” child-rearing advice amounts to something in the neighborhood of a hundred bucks off a thousand-buck TV. It’s a good deal, but not nearly good enough to get you to buy more TVs, or kids, than you thought you wanted.

Now, why is it thought that parents are “overcharging” themselves? Because they buy into the alleged myth that “nurture” matters to how their kids turn out, and nurturing is an annoying time-sink. As Mr. Caplan puts it, “belief in the power of nurture” makes us “reluctant to have more kids,” while “disbelief in the power of nurture” can make you, as it made him, “eager to have more.”

Now, if Mr. Caplan were to rest content advising parents to chill out on the basis of the idea that parenting matters less than most people think, I’d have no complaint. Seriously, Amy Chua, relax. But I find the further claim that family size is so sensitive to culturally prevalent beliefs about nurture versus nature pretty perplexing, especially coming from an economist—a genetic determinist economist!

What use is Mr. Caplan’s counsel to chillax, if you are inveterately fretful and heeding it would require defying your deepest inborn nature?

As Mr. Caplan acknowledges in his final paragraph, women ultimately control family size. So his argument would seem to be that many women have chosen to have fewer children than they might have wanted (or might have wanted to give their hectoring husbands) because the nurture myth leads them to overestimate the cost of the marginal child. Now, I’m sure Mr. Caplan is aware that the size of “vaguely normal First World families” has been shrinking across the globe, and I doubt he believes this has occurred because genetic determinism has fallen on hard times. The story of declining family size is to a great extent the story of women’s liberation. As the struggle for women’s equality has proceeded, women have enjoyed rising levels of education, income, autonomy and increasing access to effective birth control. And as women’s liberty and capability to deliberately control the conditions of their existence has expanded, family size has declined.

Economists generally begin from the assumption that we’re rational decision-makers who do the best we can to achieve our aims given the constraints we face. In Mr. Caplan’s previous book, “The Myth of the Rational Voter,” he lays out an elaborate theory of “rational irrationality” in order to explain how it is possible for voters to act on irrational beliefs about politics and policy without having to abandon the economist’s foundational rationality assumption. But Mr. Caplan offers us no analogous theory of the rationally irrational mother. He simply begins with the ad hoc hypothesis that mothers are forgoing body-reconfiguring pregnancy, excruciating childbirth and the massive time-cost of additional children (which women disproportionately shoulder) not because they are rational beings taking into full account the manifold considerations relevant to profoundly life-shaping choices, but because they are in error about the power of parenting to shape “adult outcomes.” I like it better when Mr. Caplan reasons like an economist.

Anyway, isn’t there something exceedingly odd about the argument that a single false belief can affect family size (which seems like a pretty significant “adult outcome”), but that pretty much nothing you can say to your kids makes a damn bit of difference? If our genes are so powerful, why should we think parenting style is the sort of thing susceptible to advice? What use is Mr. Caplan’s counsel to chillax, if you are inveterately fretful and heeding it would require defying your deepest inborn nature? That would be like a coupon for $100 off a $1000 TV in a language you can’t understand in a store you can’t find.

Do twin studies prove Tiger Mothering is in Amy Chua’s seething blood while Serenity Parenting burbles gladly through Bryan Caplan’s cheerful veins? I don’t know, but I hope so. I’d like to think then they’d stop telling me how to raise the kids I’m happy I don’t have, but probably they can’t help it. Despite my misgivings, I do admit that Mr. Caplan has persuaded me that if his argument convinces anyone to have an extra child, she was poised to do it anyway.

Will Wilkinson blogs about American politics for The Economist. He lives in Iowa City.

Comments (5 of 17)

I think Caplan is just suggesting that parents 'diversify', instead of over-investing in a single child.

12:05 am April 14, 2011

Claire wrote :

You hit the nail on the head about his argument, I think it smacked of the sort of needlessly contrarian viewpoint designed more to generate discussion and pageviews more than to say something meaningful about the cost of parenting.
On an unrelated note, I was wondering if anybody else thought it was odd that he based his "nature is all that matters, nurture is unimportant" argument based solely on identical twin studies? The research now has cast doubt on the methodology of those studies. Specifically, both adopted siblings are invariably raised in a somewhat similar environment in terms of parental achievements and income, based on the people who choose to adopt children. It may even be immoral to place 1,000 sets of identical twins with an abusive family in the ghetto and a set of nurturing doctors, and to see what happens. Nurture finds us, even when we think that nature alone is what rules the roost.

11:15 pm April 13, 2011

mkburr wrote :

Genius.

10:56 pm April 13, 2011

Anonymous wrote :

You're an idiot.

7:25 pm April 13, 2011

Joe wrote :

I really don't think Caplan was proposing that this supposedly false belief and overinvestment is the explanation for the overall decline in family size in developed societies! I think he was assuming that that belief does play a role for a non-trivial number of people in the demographic who read the Wall Street Journal, and who are in his social stratum. It doesn't seem like that bad of an assumption, from that perspective. That said, I agree that he is really overselling the nature over nurture point, and that he uses some pretty crude consumer behavior analogies to make his case.